(Technical Field)
The present invention relates to a control apparatus for an electric rotating machine.
(Related Art)
For example, there are vehicles in which idling stop control is performed to reduce fuel consumption and exhaust gas. To perform the idling stop control, the configuration including an electric rotating machine (motor generator), a so-called ISG (Integrated Starter Generator), that can perform power generation and power running is in practical use. The ISG has an inverter and a motor section, and performs electric power control for power generation or power running by turning on and off switching elements of the inverter.
A fail-safe technique is known which stops gate control for switching elements performed by a controller of an ISG and forcibly shifts the function of the ISG to power generation only, when an abnormality has occurred in the controller of the ISG (JP-A-2005-65389).
For example, when a short circuit abnormality has occurred in an inverter due to, for example, an on failure of a switching element, an overcurrent flows through switching elements of upper and lower arms. Due to this, there is a concern that the switching elements may be damaged. Hence, when such a short circuit abnormality has occurred, a process for turning off all the switching elements of the inverter is performed as a protection process. In addition, when a short circuit abnormality has occurred, the power-supply voltage of the inverter decreases. Hence, typically, whether or not the power-supply voltage has decreased is determined, and the protection process is performed based on the result of the determination.
However, a power-supply line leading to a battery is considered to be connected to an electric load other than the ISG. A decrease in the power-supply voltage may be caused due to, in addition to the short circuit abnormality in the ISG, voltage fluctuation due to the driving of the electric load. In this case, according to known techniques, the protection process for the ISG is performed regardless of whether the decrease in voltage is caused due to the ISG or a factor other than the ISG. Hence, when the decrease in voltage is caused due to a factor other than the ISG, and the protection process for the ISG is not essentially required, there is a concern that power running and power generation functions may be unnecessarily lost due to the protection process.